Component provided with a description

ABSTRACT

For labeling a component ( 2 ) provided with a metallic cover layer ( 13 ), it is proposed that at least one further contrast layer ( 14 ) be arranged over the cover layer, said at least one further contrast layer ( 14 ) producing an optical contrast with the metallic cover layer and being capable of being eroded by means of a laser for producing a labeling.

[0001] The invention is directed to a component, particularly to aminiaturized, passive component.

[0002] For identifying electrical, electronic and, in particular,passive components, these are usually provided with a labeling. This canprovide information about the manufacturer, the type or thespecifications of the component and, potentially, the serial number orarticle designation. Larger components that comprise adequately largesurfaces for the acceptance of a labeling can, for example, be printedwith silkscreening in a simple way. Given smaller components havingdimensions of, for example, below 1 mm, enough printable surface forproducing a labeling is not available. Alternatively, these componentscan be labeled with a laser that still enables even the minutest fontsizes to be produced.

[0003] Only labels that are difficult to read or no labels at all can begenerated with laser labeling on miniaturized components that comprise ametallic layer on the surfaces available for a labeling since adequatecontrast cannot be achieved there by erosion of material.

[0004] It is therefore an object of the present invention to specify acomponent with, in particular, a metallic cover layer on which ahigh-contrast labeling is possible.

[0005] This object is inventively achieved by a component according toclaim 1. Advantageous developments of the invention proceed from thesubclaims.

[0006] In a component that comprises a metallic layer, particularly acover layer, on a surface available for labeling, it is proposed that acontrast layer that can be eroded with a laser be applied over themetallic layer. In this way, one succeeds in fashioning a highly legiblelabeling with high optical contrast in a simple way in the contrastlayer by means of laser labeling, i.e. by means of partial layererosion.

[0007] All layers that are simply to apply and that comprise a goodoptical contrast relative to the metallic cover layer fundamentally comeinto consideration for the contrast layer. Particularly simple to applyare those contrast layers that are compatible with the manufacturingsteps of the component. Those cover [sic] layers are especiallypreferred whose application can be seamlessly introduced into themanufacturing process of the component and that, in particular, can usethe same apparatus that are required for preceding method steps in themanufacture of the component.

[0008] In an advantageous development of the invention, the contrastlayer is generated immediately after the manufacture of the metalliccover layer, whereby the contrast layer is also preferably a metalliclayer that differs from the metallic cover layer with respect to itsoptical properties. A distinction between two metallic layers can, forexample, be achieved via the reflection behavior of the metallic layersthat, in particular, is dependent on the modification or, respectively,fine structure of the layer. Alternatively or additionally, the contrastlayer can differ from the cover layer in color or, respectively,differently colored metals can be employed for the layers.

[0009] However, other materials can be selected for the contrast layer,for example lacquer layers and, in particular, colored lacquer layers,especially lacquer layers colored black. In general, it is advantageouswhen the contrast layer exhibits a different color compared to the metallayer or, in particular, is a black layer.

[0010] Purely metallic layer combinations generated on top of oneanother wherein a good optical contrast can be generated by laserlabeling and that can be serially applied and, in particular, with thesame apparatus or a similar apparatus are, for:

[0011] a) copper/bright nickel/black nickel

[0012] b) bright copper/nickel/black nickel

[0013] c) copper/nickel (matte)/nickel (gray)

[0014] d) copper/aluminum/anodized aluminum

[0015] These layer combinations can be additionally applied over themetallic cover layer. One or two metal layers of said layer sequences,however, can also form the cover layer or co-assume functional tasks ofthe cover layer.

[0016] Preferred layer combinations are those that comprise twodifferent modifications of one and the same metal. In particular, theseare produced by means of different manufacturing conditions. Givenapplication of the metallic layers by sputtering, currentless depositionor galvanic deposition, for example, the composition or thecorresponding optical layer properties can be set by varying the methodparameters or deposition conditions.

[0017] The following metal/metal combinations, which are alsodistinguished by different metal coloration, are layer sequences thatcan be serially applied and comprise a metal layer (cover layer, too),that develop an optical contrast relative to one another and that can belabeled or, respectively, eroded with a laser:

[0018] e) nickel/gold

[0019] f) copper/nickel

[0020] g) copper/aluminum

[0021] h) copper/tin

[0022] i) copper/silver

[0023] The same deposition conditions are preferred for thesedifferently colored metal layer combinations, whereof at least the lowerlayer can be the metallic cover layer or part of the metallic coverlayer. Even though the contrast is produced here merely by means ofdifferently colored metal layers or, respectively, the metal layerregions remaining after the laser labeling, a contrast in reflection canalso be produced in addition to the contrast in color. It is therebypreferred when the upper layer (contrast layer) has poor reflectivity,but the lower layer that can be uncovered by laser labeling comprisesgood reflective properties.

[0024] An electrophoretic process is also suitable for applying acontrast layer composed of lacquer and, in particular, of black lacquer.A number of different lacquers are suitable for this, no or few demandsother than the contrast having to be made of their material or,respectively, composition. However, it is also possible to print thecontrast layer comprising a lacquer on, to dribble it on or to cast it.

[0025] The invention encounters advantageous application in componentsthat comprise or require a metallic cover layer as functional layer. Forexample, such a metallic cover layer can be a metallic cap. However, themetallic cover layer can also be a metallic housing or a part thereof inwhich an arbitrary component is arranged. Metallic cover layers are alsoparticularly employed as shielding layers against electromagneticradiation. Such a shielding can be required in order to prevent theemission of electromagnetic radiation from the component itself.However, a component is also possible that comprises a metallic coverlayer that serves the purpose of shielding against electromagneticradiation acting from the outside, particularly when the component issensitive to the electromagnetic radiation. The components are thereforepreferably components operated at high-frequency, particularlysurface-wave components for the RF range.

[0026] The invention is explained in greater detail below on the basisof an exemplary embodiment and the two Figures appertaining thereto.

[0027]FIG. 1 shows a schematic crossection of components applied on acarrier with a multi-layer metallization;

[0028]FIG. 2 shows a schematic crossection of a labeling produced in themulti-layer metallization.

[0029] Exemplary Embodiment:

[0030]FIG. 1: The preferred application of the invention is givensurface-wave components, particularly surface-wave filters that areapplied on base substrates 2 in flip-chip technology. The piezoelectriccomponent substrate 1 that carries the active component structure 6 isthereby connected face-down to the panel 2 via suitable solderconnections 5, particularly via bumps, so that the component structuresare arranged protected between component substrate and panel at a cleardistance from the latter. Preferably, a plurality of components arethereby applied on one panel and only separated after the completion ofall cover layers. As shown, the active component structures 6 can alsobe additionally covered with a cover cap 7 that is generated directly onthe surface of the component substrate 1 (chip) in an integrated processcalled PROTEC by the assignee. This leaves a clear cavity over thecomponent structures that mechanically protects it during the process.

[0031] The bumps 5 connect the terminal pads 9 on the chip 1, which areelectrically conductively connected to the active component structures6, to the under-bump metallization on the base 2. An electricallyconductive connection to the terminal metallizations 10 on the undersideof the panel 2 is produced via through-contactings 3 in the panel; theassistance thereof makes it possible to connect the component to, forexample, a circuit in SMD structure that is produced on a printedcircuit board or a module. The panel is fashioned of plastic or ceramicand is preferably two-layer. This creates a metallization level betweenthe layers, so that interconnects can be laid without intersecting.Moreover, this allows through-contactings 3 that are laterally offsetrelative to one another, these being capable of being manufacturedhermetically tight in contrast to through-contactings that lead throughthe panel 2 on a straight line.

[0032] For shielding from electromagnetic radiation, a metallic layerthat comprises a plurality of layers 11, 12, 13, 14 here is applied suchon the back side of the component substrate that it terminateshermetically tight relative to the panel 2 and thus hermetically sealsthe entire component. To this end, an under-filler 15 can be applied asseal in a previous step, said under-filler 15 annularly surrounding thecomponent substrate 1 and closing the clearance between componentsubstrate 1 and panel 2 at least in the outer region of the componentsubstrate (see FIG. 1). The under-filler 15 can be produced by applyingand curing a liquid sealing compound, particularly a lacquer or resin.For sealing, however, it is also possible to apply a plastic film, metalfoil or laminate foil (not shown in the Figure) that lies tightlyagainst the component and the base substrate.

[0033] The metallic cover layer can now be applied on the componentsubstrate or, potentially, on the seal by means of foil. For, this canensue in the form of a metallic foil. However, the metallic layer canalso be the outer layer of a multi-layer laminate foil that is utilizedfor sealing the component. It is also possible, however, to produce themetallic cover layer by metallization and subsequent galvanicreinforcement. This has the advantage that the contrast layer can begenerated in the same way immediately thereafter, preferably as furthermetallic layer.

[0034] To that end, the surface to be metallized (back side of the chip1, surface of the under-filler 15 and exposed surface of the panel 2next to the applied chip 1) is first activated, for example with PdCl₂solution at slightly elevated temperature. As first layer, a chemicalmetallization is then deposited currentless on the surface activated inthis way, for example an approximately 2-3 μm thick copper layer 11 in ahighly alkaline, chemical copper bath.

[0035] The copper layer 11 is subsequently galvanically reinforced, forexample with a further copper layer 12 in an acidic copper bath at roomtemperature. As passivation layer, a nickel layer 13 is now depositedthereover in an acidic matte nickel bath, this representing a partiallayer for the contrast of the later labeling. As contrast layerbelonging thereto, an approximately 0.3 μm thin black nickel-plating isthen produced thereover in an acidic black nickel bath.

[0036]FIG. 2: By means of selective exposure with a laser, for examplean NdYAG laser, a part of the contrast layer 14 is now selectivelyremoved, this being promoted by the high absorption of the dark, blacknickel layer. The surface of the metallically bright nickel layer 13 nowappears in the regions uncovered in this way and forms a highly visiblecontrast together with the remaining layer regions of the black nickellayer 14.

[0037] As stated, the invention is advantageously utilized givencomponents that are applied and enveloped according to the method calledCSSP (Chip Sized SAW Package) by the assignee. In contrast totraditional technique, the component substrate 1 applied on a panel 2 bymeans of flip-chip technology comprises essentially the same dimensionsas the panel 2 and therefore enables a further miniaturization of thecomponent or, respectively, of the component package. A plurality ofcomponents applied in common on a panel 2 and inventively covered aresubsequently separated, for example by sawing at a parting location 16between the soldered-on component substrates (see FIG. 1).

[0038] Of course, the invention is not limited to the employment givenSAW components. However, it is preferably employed for miniaturizedcomponents that do not enable a traditional labeling by means ofprinting because of the slight available surface and wherein a directlaser labeling is not possible due to the metallic cover layer or canonly be produced with poor contrast.

1. Component having a metallic cover layer (11, 12, 13), whereby atleast one further contrast layer (14) is arranged over the metalliccover layer, said at least one further contrast layer (14) producing anoptical contrast with the metallic cover layer and being capable ofbeing eroded by means of a laser for producing a labeling.
 2. Componentaccording to claim 1, whereby the contrast layer (14) is a metal layer.3. Component according to claim 2, whereby the optical contrast isachieved in that the cover layer (13) is a reflective layer and thecontrast layer (14) is a matte layer or vice versa.
 4. Componentaccording to one of the claims 1-3, whereby the optical contrast isachieved in that cover layer (13) and contrast layer (14) aredifferently colored.
 5. Component according to one of the claims 1-4,whereby the contrast layer (14) is a black layer and the cover layer(13) is metallically bright.
 6. Component according to one of the claims1-5, whereby the contrast layer (14) is a black nickel layer. 7.Component according to one of the claims 1-5, whereby the contrast layer(14) is an electrophoretically applied lacquer layer, a cast-on glob topcompound or a printed-on lacquer layer.
 8. Component according to one ofthe claims 1-6, whereby the contrast layer (14) is a further metal layerthat is colored differently compared to the cover layer (13). 9.Component according to claim 8, whereby the combination of cover layer(13) and contrast layer (14) comprises one of the following materialcombinations: Ni/Au; Cu/Ni; Cu/Al; Cu/Sn; Cu/Au.
 10. Component accordingto one of the claims 1-9 provided with at least one contrast layer (14)over the metallic cover layer (13), given [sic] regions (17) of thecontrast layer are lifted off with a laser labeling while uncovering thecover layer (13).
 11. Component according to claim 10 fashioned as a SAWcomponent with an RF-shielding cover layer (11, 12, 13).
 12. Componentaccording to claim 11 that is secured on a panel (2) in flip-chiptechnique, and whereby the metallic cover layer (13) is applied on theback side of the component (1) and hermetically closes this off from thepanel (2).